For example, Patent Literature 1 discloses an in-wheel motor driving device including a motor, a cycloid speed reduction gear interposed between the motor and a wheel bearing, a control device for controlling the driving of the motor and a temperature sensor mounted on the motor. When a vehicle equipped with an in-wheel motor driving device runs at low speeds, a large torque is needed, and when the motor and the speed reduction gear are overloaded, the temperature of the motor or the like tends to rise excessively. Then, the control device limits the driving electric current of the motor according to information on a temperature measured by the temperature sensor so as to prevent an excessive increase in the temperature of the motor or the like.
In addition, Patent Literature 2 discloses an inverter device for driving a motor which has two rotors, having different outputs and disposed on the same output shaft, and two stators. In this inverter device, individual inverter circuits are provided exclusively for the rotors. Then, the inverter circuit for one of the two rotors which has a smaller output is controlled with a high frequency, while the inverter circuit of the other rotor which has a larger output is controlled with a low frequency, whereby the heat value of the motor is suppressed.
Additionally, Patent Literature 3 discloses a motor control device for controlling the driving of two motors. In this motor control device, a load distribution ratio at which the total loss of the two motors becomes the least is determined based on the required outputs and detected temperatures of the motors to control the driving of the motors, whereby the increase in the temperatures of the two motors is suppressed.